84109586 ÷ 640 
We want to figure out the number of times 84109586 can be divided by 640.

On to step 1:
640 can be fit into 8 0 times, resulting in a remainder of 8.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Append the next digit (4) from the dividend to 8 and continue with: 84 / 640

Going ahead to step 2:
84 divided by 640 is 0 with a remainder of 84.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 84 after subtracting 0 from 84.
Fetch the next digit (1) from the dividend, attach it to 84 and continue: 841 / 640

Step 3:
640 can be fit into 841 1 times, resulting in a remainder of 201.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Deduct 640 from 841 and we're left with 201.
Include the next digit (0) from the dividend after 201, then repeat: 2010 / 640

On to step 4:
The number 640 fits into 2010 3 times, leaving a remainder of 90.
Put 3 as the next digit of the answer. 
Result so far: 13.0
Deduct 1920 from 2010 and we're left with 90.
Include the next digit (9) from the dividend after 90, then repeat: 909 / 640

Advancing to step 5:
909 divided by 640 is 1 with a remainder of 269.
Write down 1 as next digit of the result. 
Result so far: 131.0
Subtract 640 from 909 to get 269.
Grab the next digit (5) from the dividend, add it to 269, then carry on: 2695 / 640

Let's proceed to step 6:
640 goes into 2695 4 times with a remainder of 135.
Use 4 as the next digit of our solution. 
Result so far: 1314.0
The remainder is 135 after subtracting 2560 from 2695.
Take the next digit (8) from the dividend and append it to 135, then repeat: 1358 / 640

Let's proceed to step 7:
640 goes into 1358 2 times with a remainder of 78.
Record the quotient 2 as the next digit in the result. 
Result so far: 13142.0
Deduct 1280 from 1358 and we're left with 78.
Include the next digit (6) from the dividend after 78, then repeat: 786 / 640

Step 8:
If we divide 786 by 640, we get 1 and a remainder of 146.
The next digit of our result is 1. 
Result so far: 131421.0
If we take 640 away from 786, we end up with 146.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1460, and continue the process.

Going ahead to step 9:
The number 640 fits into 1460 2 times, leaving a remainder of 180.
Write down 2 as next digit of the result. 
Result so far: 131421.2
If we subtract 1280 from 1460, we get 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1800, and continue the process.

Advancing to step 10:
When dividing 1800 by 640, we get 2 with a remainder of 520.
The next digit of our result is 2. 
Result so far: 131421.22
Deduct 1280 from 1800 and we're left with 520.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5200, and continue the process.

The final outcome is 131421.22, with a leftover of 0.52.